1. Field of the Invention
The invention relates to the field of electronics and electrotechnology and can be used in production of capacitors for creation of elements (cells) of memory for integrated microcircuits, in high-Q contours, in decoupling elements, and in reserve power supplies. Such memory cells can be used as sources of current for a mobile communication facility, in energy installation of an electric vehicle, and also for buffer accumulation of electrical energy with high specific density on the order of 1–1.5 MJ/kg.
2. Background Art
Electrical capacitors having a large specific capacity on the base of solid dielectrics are known. For example the capacitor on BaTiO3 dielectrics have large permittivity ∈>1000 and specific capacity of about 0.3 F/cm3. However, in the majority of the power applications such specific capacity is not enough. To increase specific capacity different methods are applied. A most effective method is nanostructuring of dielectrics such as BaTiO3 by creation of nanosize clusters with a shell [1], or creation of thin nanosize films with metal doping [2]. With the help of such an approach, it is possible to increase permittivity up to ∈=105–106 and to achieve specific capacity on the order of 100–1000 F/cm3. In result, it is possible to receive specific energy reserved in the capacitor of on the order of 2–20 MJ/kg. The specific energy reserved in such capacitors considerably exceeds one, reserved in lead (0.08 MJ/kg) and nickel (0.15 MJ/kg) electrochemical accumulators and is commensurable with specific energy, reserved in best lithium accumulators (0.5MJ/kg) [3].
Obviously, the advantage of capacitors compared to electrochemical accumulators is rapid accumulation of energy and unlimited quantity of the recharging cycles. However, in capacitors made in accordance with the foregoing patents the barium titanate with a high degree metals doping is used. It results in the transformation of dielectric to the semiconductor. In result, there is large leakage current that results in rapid loss of the stored energy. Hence, the application of such capacitors for long-term storage of energy is not effective. Besides, as the reserved energy increases greater than 2 MJ/kg the film BaTiO3 cracks. Thus, it is impossible to achieve a limiting value of 20 MJ/kg practically for a while yet.
Another type of capacitors with high specific capacity is known. It is the so-called supercapacitors which have a double electrical layer formed between liquid electrolyte and electrode. To increase the specific capacity the electrode is made from various materials with a large specific surface, for example [4], the patent [5]. Specific capacity of such capacitors is on the order of 2–46 F/cm3 at the maximal specific energy, reserved by them up to 0.045 MJ/kg. The limiting reserved energy in such capacitors is determined by potential of electrolyte dissociation which does not exceed 2–3 V. Such capacitors are quickly charged and have unlimited recharging cycle. However, the electrolyte used makes it unserviceable and also increase leakage current that reduces energy storage time. Besides, the low specific reserved energy does not allow replacing by it the electrochemical accumulators in practically important cases.
In the listed above solid-state and liquid accumulators the mechanism of carry of ions is used. For example, in BaTiO3, ions are moved together relatively to a crystal lattice, and in liquid electrolyte the carry of ions is carried out due to mechanical moving of ions relative to a surface of electrodes. Such process of movement of heavy ions limits the high-speed characteristics. Therefore, such capacitors cannot be applied in elements of memory of super high speed integrated circuits.